Sputter deposition is a technique used to produce a metallic layer in various manufacturing processes used in the semiconductor and the photoelectric industries. With advances in the semiconductor and photoelectric industries, there are needs for sputter targets that meet one or more electrical requirements, durability requirements, and processability requirements. For example, there is a need for sputter targets that are easier to process, that are less expensive, and that can be used to produce more uniform films. Furthermore, as the size of displays increases, the economic benefits of even modest improvements in performance becomes amplified. Slight variations in compositions of a sputter target could possibly lead to significant property changes. Moreover, different manners in which a target is made may lead to varied properties resulting from a target made using the same composition.
Sputter targets made from a metal such as molybdenum, methods for preparing them, and their use in flat panel displays are described in U.S. Pat. No. 7,336,336B2, and in U.S. Patent Application Publication No. 2005/0189401A1 by Butzer et al, published on Sep. 1, 2005, each of which is incorporated herein by reference in its entirety.
Sputter targets containing molybdenum and titanium, methods for preparing them, and their use in flat panel displays are described in U.S. Pat. No. 7,336,824B2 and in U.S. Patent Application Publication Nos. 2008/0314737A1 by Gaydos et al. published on Dec. 25, 2008, 2007/0089984A1 by Gaydos et al., published on Apr. 26, 2007, and 2007/0251820A1 by Nitta et al. published on Nov. 1, 2007, each of which is incorporated herein by reference in its entirety.
Sputter targets containing molybdenum and a second metal are described in U.S. Patent Application Publication No. 2004/0263055A1 by Chao et al. published on Dec. 30, 2004, 2007/0122649A1 by Lee et al. published on May 31, 2007, and 2005/0230244A1 by Inoue et al. published on Oct. 20, 2005, 2008/0073674A1 by Cho et al. published on Mar. 27, 2008, and 2005/0191202A1 by Iwasaki et al. published on Sep. 1, 2006, each of which is incorporated herein by reference in its entirety. In the manufacture of many devices, thin film products are often built up layer by layer with one or more material removal steps (e.g., etching). To accommodate a wide selection of materials for enhancing design choice, it is attractive to be able to selectively control thin film etch rate (i.e., the rate of removal of material by etching). For example, it is attractive to be able to achieve certain etch rates by selection of an appropriate sputter target. For example, it is attractive to be able to achieve certain etch rates by selection of an appropriate sputter target. It may be desirable for a layer deposited from a sputter target to have an etch rate that is compatible with the etch rate of one or more other layers (e.g., etch rates that are the same or differ by less than about 25%) and/or to have an etch rate that is different (e.g., by about 25% or more) from the etch rate of one or more other layers.
For example, for some applications there continues to exist a need for sputter targets that produce deposited layers having relatively low etch rates, such as etch rates in ferricyanide solution lower than the etch rate of a layer deposited from a sputter target consisting of 50 atomic % molybdenum and 50 atomic % titanium. There is also a need for sputter targets for producing deposited layers having one or any combination of a strong adhesion to substrates, a good barrier properties, an ability to reduce or prevent the formation of copper silicon compounds (such as copper silicide) when placed between Si-containing and Cu-containing layers, or a relatively low electrical resistivity (e.g., about 60 μΩ·cm or less). Additionally, there is a need for sputter targets having one or more of the above properties, that is prepared from a heterogeneous material that can be processed into a sputter target using a step of rolling.